Many New Yorkers returned to work on Tuesday morning on the shiny new Second Avenue subway, a long-delayed project that took nearly a century to bring to reality. The Metropolitan Transportation Authority, which runs the city’s subway system, opened the first segment of the line to the public on New Year’s Day with three new stations at East 96th Street, East 86th Street and East 72nd Street.

But it was on Tuesday that the new subway line faced its first big test as commuters piled on. For some, it was a faster way to work or a more convenient way tor travel. For others, it was simply an experience not to be missed.

Vicente Herrera, 38, a home health aide, snapped selfies at the East 72nd Street station. He said he had never seen subway tracks that looked so good — not caked in black grime. Mr. Herrera, who lives in Washington Heights, inhaled deeply. “The smell,” he said. “It smells like new.”

The Second Avenue subway held the tantalizing promise of a more pleasant commute for subway riders. There were many reasons: Fewer blocks to walk. Precious minutes shaved off daily treks. Not having to wedge onto the perpetually packed trains and platforms of the nearby Lexington Avenue subway, the most crowded subway line in the United States. And no rats — yet.

The new line also includes a new entrance to the subway station at East 63rd Street and Lexington, where it will connect directly to the existing Q train route running south to Coney Island. On Tuesday morning, the Q roared through the new stations with no delays or major problems, according to M.T.A. officials.

Image

Catching the Q train at the new 86th Street station.CreditJohn Taggart for The New York Times

John Raskin, the executive director of Riders Alliance, a transportation advocacy group, said the Second Avenue subway would bring needed relief to the Upper East Side. “I think people will start to notice the difference right away,” he said. “Now the challenge will be fixing the rest of the system to benefit everyone else who is trying to get to work.”

Mr. Raskin said that while he had heard no complaints about the Second Avenue subway on Tuesday, there were plenty of other problems. The 1,2,3,4,5,6, B and D trains had all been delayed for a variety of reasons, including a person who jumped in front of a southbound 1 train, unauthorized people walking on or near tracks, a sick passenger, a track fire and signal problems.

The Second Avenue subway attracted 48,200 riders on Sunday, M.T.A. officials said. Numbers for Monday and Tuesday were still being collected. Ridership is expected to eventually rise as high as 200,000 daily as more commuters return to work from the holiday break and become familiar with the line, they said.

Veronique Hakim, the president of New York City Transit, which is part of the M.T.A., said that she had been “hopscotching” along the new line on Tuesday. Riders, she said, seemed to appreciate the larger platforms and improved service. “It’s a very different experience to riding the Lexington line,” she said.

The benefits of the new subway line already appeared to have caused a spillover effect. On Tuesday morning, some Lexington Avenue trains and platforms appeared less crowded, in part because foot traffic seemed lighter after the holiday but also because there was now another option. At the 86th Street Station, a platform controller for the M.T.A. who did not give her name said that normally by 7:45 a.m., two or three rows of people would be waiting to board the 6 train. Today, there was only a single row.

“I have a lot of hope it will relieve some of the congestion,” Marie Kallio, 50, an administrator from the Bronx, said as she waited on the platform.

Emilia Goued, 14, a high school student, said she often had to push her way onto the 4 or 5 express trains and wait for several to go by because there was simply no room. Not today. “I feel like I can get on any express train that comes,” she said.

Image

Commuters at the 86th Street station.CreditJohn Taggart for The New York Times

Some riders could not wait to try out the Second Avenue subway. At the East 96th Street station, where a sign announced that service would start at 6 a.m., a group huddled outside 15 minutes early. Several tried to slip in past a gate at the entrance, only to be turned back into the morning chill by subway workers.

“Two minutes,” one worker said aloud, as the clock ticked down.

Jim Hopkins, 61, was one of the first through the turnstile. “This is perfect for me,” said Mr. Hopkins, the chief operating officer of a real estate investment business who lives on East 95th Street, estimating that he would save about 10 minutes on his new commute to Herald Square. “Now I can get in a little earlier and work a little later.”

Ten blocks south, at the East 86th Street station, Katherine Chango, 19, of Brooklyn, waited on the platform to go home after delivering newspapers on the Upper East Side. “I wanted to check it out for the first time,” said Ms. Chango, who said the new line was more convenient for her than the Lexington Avenue subway. “It’s more of a struggle to take the 6 or the 4 for me,” she said.

Of course, some riders still found something to gripe about. A few said that trains took longer to arrive than they expected or wanted. At the East 86th Street station, several commuters waited impatiently for a southbound train that, according to an electronic information kiosk, was “arriving now.” In fact, it took a few more minutes.

Still, United States Representative Carolyn B. Maloney, a Democrat and a leading advocate for the Second Avenue subway for more than two decades, said she had heard “overwhelmingly positive” feedback. “Many have been waiting for it their whole lives,” she said.

By its third day of service, the Second Avenue subway already had fans.

Duane Butler, 62, wore a black baseball cap with a yellow Q train logo and “2nd Av Local” stitched on the back. Mr. Butler, who lives on 90th Street between First and Second Avenues, was on his way to work at a Barnes & Noble corporate office near Union Square. In his jacket pocket was a stopwatch to time his first commute on the new line. “I clicked it on as soon as I walked out the door,” he said.

This was not Mr. Butler’s first time on the new subway line. He has been riding it since it opened.

“I think it’s breathtaking,” he said.

Emily Palmer, Sean Piccoli and Nate Schweber contributed reporting.

A version of this article appears in print on , on Page A19 of the New York edition with the headline: Weekday Commuters Take Their First Turn on the 2nd Avenue Subway. Order Reprints | Today’s Paper | Subscribe